Chiuro is a comune in the Province of Sondrio in the Italian region of Lombardy, located about 100 kilometres northeast of Milan and about 9 kilometres east of Sondrio, on the border with Switzerland. As of 31 December 2004, it had a population of 2,499 and an area of 51.8 square kilometres. The municipality of Chiuro contains the frazioni Castionetto and Casacce.